Darren McGrady, 55, was Princes Diana's personal chef from 1993 until she died in 1997. Before that, he was personal chef to Queen Elizabeth II. For the past 20 years McGrady has lived in Dallas, where he first worked as a chef for a private family then started his own catering business. "The Royal Chef at Home," a follow up to his first cookbook, "Eating Royally," will be published Sept. 1.

In an interview with USA TODAY, McGrady recalled Princes Diana's interest in healthy eating, meals with her sons, princes William and Harry, and how she inspired him to do charity work. She died 20 years ago this month. Here are McGrady's words, edited and condensed for clarity:

My first job at Buckingham Palace was right at the very bottom — chef No. 20 of 20. I worked on the vegetable section cooking for palace staff. It was horrible. Frozen vegetables for 300. I met Princess Diana at Balmoral Castle (the queen's vacation home in Scotland) and over time, I became a friendly, familiar face to her, although I was never her friend. I was staff. I never called her Diana. It was "Your Royal Highness" to the end, even after she lost the title and would say, "you don't have to call me that."

At Balmoral and Buckingham Palace, she would come down to the kitchens and ask if she could have a yogurt or maybe some orange juice for her or one of the boys. I got to dance with her at balls. When she separated from Prince Charles (in 1992), I thought "Oh my gosh I'll never see her again." But then I got a call asking if I would be interested in being her chef so I moved across to Kensington Palace (her London home).

At Buckingham Palace, the food was very traditional French, very rich, lots of creams, lots of butter. When I moved over to Kensington Palace, the princess had gotten her life back on track. She had conquered the bulimia and wanted to eat well. She said to me: "I want you to take care of all the fats, and I'll take care of the carbs at the gym."

One time she said: "Make me the tomato mousse you made for President Ronald Reagan at Windsor Castle, and I said, 'You can't have that Your Royal Highness it's got mayonnaise, sour cream, it's got double cream.' She said, 'Well, make me a fat-free version.'" That's when I started to change all my recipes. I had to find a way to make her healthy food while keeping the comfort and nursery foods for William and Harry. It was exciting to me because in those days, this was something entirely new.

Another time she came in and said: "I need a juicer. I want to start having fresh juices." So I was dispatched in a taxi to Selfridges (a fancy London department store) to get a juicer, and I started making juices for her with carrots, celery, parsley, spinach. One time, she wanted one with just beetroot in it. I advised her against it, but she insisted. A few hours later she came back into the kitchen and said, 'Oh my God, Darren, you poisoned me." Her face had gone all blotchy from the beetroot.

Prince Charles and Lady Diana Spencer at their wedding ceremony July 29, 1981, at St. Paul's Cathedral. The train to Diana's voluminous wedding gown, designed by Elizabeth and David Emanuel, was a fantastic 25 meters (about 82 feet). The sanctuary was full of aristocracy and world leaders. Many referred to it as the wedding of the century. AP

Prince Charles and his bride proceed down the aisle of St. Paul's Cathedral at the end of their wedding, which had an estimated global television audience of 750 million. Prince Charles, 32, was under pressure to take a wife. Diana was 20 on their wedding day. AP

Even 34 years later, interest in the wedding remains high. A collection of unpublished photographs of Diana and Charles at Buckingham Palace following the ceremony was released Aug. 12. The images are believed to have been taken by Lord Patrick Lichfield and are to be auctioned by RR Auction in Boston on Sept. 24. RR Auction handout via EPA

One of the most important duties of a royal couple is to produce an heir. Their first son, Prince William, was born June 21, 1982. Here, they play during a photo session at Kensington Palace in London Dec. 22, 1982. Dave Caulkin, AP

Prince Charles gets a kiss from his wife as she presents him with a prize after he had played for the England II polo team against Chile at the Guards Polo Club in Windsor on July 27, 1986. John Redman, AP

With her beauty and style, Princess Diana quickly became the most photographed and emulated royal. She arrives at the Cannes Film Festival for a gala honoring actor Sir Alec Guinness. She wears a pale blue silk chiffon strapless dress with a matching chiffon stole designed by Catherine Walker. Tim Graham Picture Library via AP

The public loved Diana's youthful vibrancy and that she insisted on raising her sons to be normal children. It was clear she enjoyed being with them as much as possible. Here, she jumps from a personal watercraft as Prince Harry looks on July 17, 1997, in Saint-Tropez. Lionel Cironneau, AP

They continue to make appearances as a family, in 1995 attending the VJ-Day commemorations at Buckingham Palace. However, the Palace confirmed Dec. 20, that Queen Elizabeth wrote a letter to both the Prince and the Princess telling them they should get a divorce. The divorce was final Aug. 28, 1996. Neil Munns, AFP

Undeterred, Princess Diana keeps up with her philanthropic interests, talking with amputees at the Neves Bendinha Orthopedic Workshop on the outskirts of Luanda, Angola, Jan.14, 1997, to promote awareness about land mines. Sitting on Diana's lap is 13-year-old Sandra Thijica, who lost her left leg to a land mine in 1994. Joao Silva, AP

Always conscious of her appearance, Diana sprints to her car on Aug. 21, 1997, after leaving a gym in west London. The princess struggled to build a new public and private life after her turbulent divorce. Tony Harris, AP

On Aug. 30, 1997, Dodi Fayed, left, arrives at the Ritz Hotel in Paris with Princess Diana. He's seen on this still from a security video. Princess Diana's bodyguard, Trevor Rees-Jones, follows Fayed. AP

Diana is seen on the security video going through the doors at the Ritz Carlton. Just hours later, Diana, Fayed and their chauffeur died from injuries sustained in a car crash in Paris in the early hours of Aug. 31, 1997. AP

A photo taken by Jacques Langevin on the night of August 31, 1997 shows Diana Princess of Wales (head turned away in backseat), her bodyguard, Trevor Rees-Jones, left, and driver Henri Paul shortly before the fatal crash. Rees-Jones was the only one in the car to survive the crash. The photo was presented as part of the evidence at the Scott Baker Inquest into the crash, in which the jury found that Diana and Fayed had been unlawfully killed because their driver and the pursuing paparazzi were reckless. Getty Images

Police prepare to take away the damaged car in the Pont d'Alma tunnel. A three-year inquiry into the death of Princess Diana, 36, and Dodi Fayed, 42, concluded that allegations of murder were unfounded and that there is no reason to suspect the involvement of the royal family, a senior police officer said on Dec. 14, 2006. Jerome Delay, AP

Queen Elizabeth accepts flowers from a well-wisher after arriving at Buckingham Palace Sept. 5, 1997. The press scolded the royal family for not displaying more emotion regarding the tragic death of the Princess. Queen Elizabeth finally made a televised speech from Buckingham Palace five days after the accident. Adrian Dennis, AP

Charles, Prince of Wales, right, and his sons Prince William, 15, center back, and Prince Harry, 12, center front, greet well-wishers and receive floral tributes for Diana at Kensington Palace Sept. 5, 1997. William, Harry and their father returned to London in preparation for Diana's funeral at London's Westminster Abbey the following day. REBECCA NADEN, AP

Business magnate Mohammed Al Fayed covers his face as he leaves funeral of Princess Diana with his wife, Heini. Al Fayed's son, Dodi, was killed along with the princess and their driver. Al Fayed alleged the crash was the result of a murder plot. He insisted that the princess was pregnant with his son's child and the House of Windsor would not tolerate a union between Diana and Dodi because he was Muslim. Santiago Lyon, AP

Mourners weep outside the funeral for Diana as they listen to a broadcast of Elton John sing. The couple were waiting for the funeral procession to reach Althorp Estate in central England, Diana's final resting place. Max Nash, AP

All I know about her bulimia is that when I started working for her, she had confronted it and gotten help. I was there as a chef only, and it wasn't my job to give her advice. There was never any food-binging or anything like that. She liked eating healthy salads.

However, when the boys were with her, they could have anything they liked: fried chicken, potato skins, roasted potatoes. They would often ask her why she wasn't eating the same things as them. So I would take the fat off her chicken, and with the potatoes, I would dip them in egg white and paprika and put them to one end of the dish and she would know they were for her. She wanted to eat healthy. She looked the best she ever did. She never ate red meat. She loved fish, stuffed bell peppers.

It was only if she was entertaining, and especially if it was men she was entertaining, that she would have lamb. Once, Clint Eastwood visited Kensington Palace for a presentation related to a charity. "Let's do a rack of lamb," she said.

Afterward, Eastwood asked to meet me and said, "that's the best lamb I ever tasted." I said, "Thank you, sir, did it make your day'?' He laughed and I laughed and the princess, of course, had no idea what we were talking about. She hadn't seen (his 1971 movie Dirty Harry).

The night she was killed, I had the food all ready. I never talk about the food I was going to prepare for her when she died.

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Princess Diana's death on Aug. 31, 1997, shocked the world and left millions grieving her loss. From her sons, Prince William and Prince Harry, to celebrities like Elton John and Nicole Kidman, mourners came together in the days (and years) following her death to honor the late princess. Sang Tan, AP

Queen Elizabeth II and Prince Philip, Duke of Edinburgh, walked along the sea of floral tributes to Diana at Buckingham Palace upon their arrival in London on Sept. 5, 1997. JOHN STILLWELL, AFP/Getty Images

Prince William and Prince Harry bowed their heads as their mother's coffin was taken out of Westminster Abbey following her funeral service. Prince William was 15 and Prince Harry was 12 when she died. ADAM BUTLER, AFP/Getty Images

Terry Hutt from Cambridge, England, who had been coming to Kensington Palace for 10 years on the anniversary of the death of Princess Diana, stood outside the palace in London on Aug. 31, 2007. LEFTERIS PITARAKIS, AP

Pavel Nowak, 37, traveled 1,200 miles by bus from Poland to be in Paris for the anniversary of Diana's death.
He brought a message and flowers to honor her the day before the 10th anniversary of her death. JEAN AYISSI, AFP/Getty Images

People took pictures and stood next to photographs, notes and flowers placed in memory of Diana above the Pont de l'Alma tunnel in Paris on Aug. 30, 2007, the day before the 10th anniversary of her death. JACQUES BRINON, AP

She was supposed to be flying into Heathrow Airport. William and Harry were coming down from Balmoral. They were going to spend a few days with us before returning to school. I got up in the morning, switched on the TV and I remember the presenter saying, "For those of you just joining, Princess Diana has died in a car accident." I thought it was a stunt or a bad joke, but it was on all the channels: We only had four in those days. I couldn't believe it.

I called my wife and my parents. They had seen it on the TV, too. I was at home so I called the Kensington Palace, but couldn't get through. I went into work and took the food with me. I just couldn't accept that she wasn't coming back. I went into work and in the office where the secretaries were, the fax machine started. It was her last will and testament being faxed through. Everyone began crying.

The next week was one of helping and packing and organizing what she wanted for the funeral. It was just awful. Then, when her body came back, all the staff were invited to a viewing at the Chapel Royal (a private chapel at St. James's Palace in London). The day of the funeral, we all lined up outside Kensington Palace to say goodbye to her.

All these years later, what I remember about her are the fun times, treating the boys, the huge shrills of laughter at Kensington Palace. She had a really naughty sense of humor. I still recall seeing her in her dressing gown and robe, with her hair up in a towel to dry and no makeup on and just looking naturally gorgeous.

Before I worked for Princess Diana, people would sometimes ask me to organize a charity dinner or make donations to this and that and I would say, "No way, why?"

Princess Diana was patron of 109 charities, and I saw the difference she made.

I once overheard her saying to the butler that she wanted 50 blankets. It was the middle of winter and cold and miserable outside. He replied, "Your Royal Highness, we can turn the heating up if you want." She said she had just been driving through King's Cross (an inner city area of London) and saw homeless people going through trash bins looking for cardboard boxes to keep warm. So she got these blankets and drove back to King's Cross and she pulled up at all these trash bins in the area and put a couple of blankets in each one in the hope that people would find them.

That's what inspired me, and people around the world, about her. The difference she could make just by doing a little bit of charity. It's why I now work with homeless shelters and domestic violence shelters, why I speak in public about her, and why I donated all the royalties from my first book to charity. I hope that by listening to fun stories about her I can encourage others to do something, to be kind.